Using utf8-string in combination with the GHC native encoding stuff (setting the encoding of the handle) seems like it'd lead to double-escaping. I've only ever used utf8-string on earlier GHCs, before there was supported for specifying the encoding of handles.
– solidsnackMay 30 '10 at 2:22

Which file do you mean -- the output file or the source file?
– solidsnackMay 30 '10 at 2:38

You have an output file? I thought the output was in the Terminal... The input file must be encoded in UTF8. But in your case, I suppose the problem lies in the Terminal's encoding.
– Olivier VerdierMay 30 '10 at 7:07